Lance Cpl. David P. Fenn II: The Polk City, Florida, resident joined the Marines in June 2010 and was promoted nine months later. In that time, he'd deployed to Afghanistan where, among other honors, he earned a NATO Medal-ISAF Afghanistan and Afghanistan Campaign Medal. The mortarman was 20.

"Remember him as he was and as who he could have been and in the future," retired Camp Lejeune Marine George Barrows told CNN affiliate WITN. "After all, he did it for our country."

Pfc. Joshua M. Martino: The 19-year-old from Clearfield, Pennsylvania, was a mortarman in the regiment. He joined the Marines in July, but already had earned the National Defense Service Medal and Global War on Terrorism Service Medal.

Friends said Martino wanted to be a Marine all his life and joined the Corps right out of high school, affiliate WTAJ reported.

Just Watched

7 Marines killed during training exercise

"I not only salute him in his passing, but I salute everyone ... in the armed forces today," said Cmdr. David Gralla of Veterans of Foreign Wars Post 813.

Martino was engaged to his high school sweetheart and the couple were planning a wedding next year.

Lance Cpl. Roger W. Muchnick Jr.: The 23-year-old hailed from the southwestern Connecticut town of Fairfield and ended up in Afghanistan as a mortarman with the 1st Battalion, 9th Marine Regiment.

Like his fallen colleagues, he amassed a host of honors in his military career, such as the Global War on Terrorism Expeditionary Medal and Sea Service Deployment Ribbon.

Muchnick played sports at Eastern Connecticut State University before leaving school early to enlist. The decision wasn't a surprise to his lacrosse coach Justin Axel.

"I knew that he would thrive in that situation. He was that kid that would do everything you tell him to do, was great at following orders," Axel told affiliate WTNH. "He was just one of those tough, hard-nosed kids that you'd just dream of having."

Cpl. Aaron J. Ripperda: At 26, he was the most senior of those killed Tuesday, both in his age and rank. The Madison, Illinois, resident joined the Marine Corps in September 2008, with his latest promotion to corporal coming in April 2011. Among his numerous honors were a Navy Unit Commendation and a Humanitarian Service Medal.

Ripperda was just nine weeks away from ending his career in the military, after serving tours in Haiti and Afghanistan, his father, Kurt Ripperda, told affiliate KSDK. His parents were relived once he came back to the States, figuring he was safer closer to home.

"No matter if it would've been nine weeks or three years, it just hurts," Ripperda said. "He was so close to getting out, but he was a good Marine. I was proud of him."

Ripperda loved cooking and sailing, and had plans to buy a new boat once he moved back home.

Lance Cpl. Joshua C. Taylor: The Marietta, Ohio, resident, 21, was a teenager when he joined the Marines in June 2010. In 2011, the decorated mortarman was promoted to lance corporal, the same year he deployed to Afghanistan as part of Operation Enduring Freedom.

His fiancee Abby Malone said the couple was planning to marry in May, according to affiliate WOOD-TV. Malone told the station she is "more proud (of Taylor) than I can say."

Lance Cpl. Mason J. Vanderwork: Another mortarman with a host of medals to his name, the 21-year-old was from Hickory, North Carolina. He, too, served in Afghanistan and accumulated a number of medals along the way.

At St. Stephens High School where he graduated in 2010, his former football coach Chip Watts said he was like a son to him and a tough team player.

"Pure tenacity. Work ethic. Desire," Watts told affiliate WSOC. "Whatever the kid did, he did it 100 miles per hour."

Vanderwork leaves behind a wife.

Lance Cpl. William T. Wild IV: In October 2010, the Anne Arundel, Maryland, resident joined the Marines. By December 2011, the mortarman had earned his new rank, and he also earned a number of recognitions, such as the Combat Action Ribbon and Global War on Terrorism Expeditionary Medal. He was 21.

Authorities still don't know how the men died. McNulty said Wednesday they know only that the "60 mm mortar system failed to function as designed," and are trying to find out why.

Hawthorne Army Depot, about 140 miles southeast of Reno, is used for storing ammunition and weapon stocks awaiting demilitarization. The facility also provides high-desert training facilities for military units.

The night after the incident, the Marines issued a statement saying that 60 mm mortar rounds and tubes used to fire them are being pulled pending the investigation.

In addition to the dead, eight service members were injured in the explosion. The Wednesday night update from the Marines indicates that a Navy Corpsman remains "very seriously injured," while five others are "seriously injured." Two Marines have been treated for minor injuries and released.